In this specification, the term “aggregate material” means different types of mined or quarried or natural mineral materials, like gravel, sand, ores, coal, different kinds of soil materials like loam and peat, different kinds of construction waste materials like concrete, bricks and asphalt as well as organic materials like timber wood chips, etc.
In this specification, the term “processing” of aggregate materials means feeding, shredding, crushing, screening, separating, washing and conveying of aggregate materials.
In aggregate material processing plant generally, processing capacity is heavily influenced by the ability to quickly and effectively deliver the processed material away from the plant. To achieve this, it is known to provide lateral conveyors which extend transversely of the plant, possibly in addition to longitudinal conveyors. While the manner in which the lateral conveyors are connected to the plant is relatively simple for the operating position, major problems arise in ensuring that the overall width and height of the mobile plant is within certain dimensions when carrying such conveyors during transport. Another problem is ensuring safety, on-site, in movement of the lateral conveyors to a position for transport of the mobile plant. A further problem lies in the support of the lateral conveyors during operation and when travelling inside the worksite with the conveyors in the working position: the conveyors are subject to high stresses due to their own weight, the weight of the screened material on the belt and vibrations caused by uneven and/or soft soil at the worksite. A still further problem is that of providing for easy and safe maintenance or repair of the lateral conveyors on-site or at a workshop.
EP 0641 607B describes a known mobile aggregate material processing plant comprising a chassis having a pair of longitudinal beams mounted on wheels and supported on jack legs.
The plant is provided with two lateral conveyors each of which comprises a tail section a middle section and a head section. The head section delivers processed material to form a stockpile of material. The conveyors are folded from the working position to the transport position by a pair of hydraulic rams. In the working position the conveyor is supported on the chassis by a support extending between the middle section and the tail section of the conveyor, the tail section being fixed to the chassis of the mobile plant. The head section of the conveyor is left unsupported.
The amount of material which can be processed by the plant is determined in part by the length of the lateral conveyors. The longer the conveyors are the higher and bigger in volume the stockpiles can be and the less you have to reserve resources for transferring the material away from the machine's stockpiles. In some instances, only one feeding machine; e.g. a wheel loader, is used for both feeding the machine and removing the processed material from the stockpiles. The bigger the stockpiles are the more freedom for planning the feeding/removing work and the less unplanned breaks have to be included in the job.
The dimensions of the conveyors in the transport position are limited by the permissible transport dimensions of the machine, as regulated in the road transport regulations. Neither the conveyors nor their supports, nor any other part of the plant is allowed to exceed these dimensions. If, for example, the chassis is dimensioned to be exactly within the permissible transport width, then the conveyors and their supports must not project laterally beyond the chassis.
EP 0641 607B provides a good solution for folding the lateral conveyors from a working position to transport position making it possible firstly to fold the middle section around the first axis being substantially parallel to the longitudinal axis of the chassis of the plant and secondly to fold the head section around the second axis substantially parallel to the lateral axis of the chassis of the plant, and back. So far, it has been a problem, to easily and effectively support such foldable conveyors.
In EP 0641 607B the path of the head section of the conveyor from the working position to the transport position is relatively complicated. So far it has not been possible to provide foldable support beams for the head section, which is easy to use and does not challenge the permissible transport dimensions of the plant. The manufacturers have had to settle with a foldable support beam extending between the middle section and the tail section of the conveyor, as the path of middle section from the working position to the transport position is much simpler than that of the head section. Anyhow, this sort of support leaves the head section unsupported, which makes the conveyors subject to high stresses due to their own weight, the weight of the screened material on the belt and vibrations caused by uneven and/or soft soil at the worksite while working or travelling inside the worksite with the conveyors in the working position.
Manufacturers and users of such plants have tried to solve the problem by extending the length of the middle section of the conveyor to provide a better support with foldable support beams. However, this would challenge the transportation height of the plant. Also detachable, non-foldable, supports between the conveyor's head section and the plant chassis and/or the ground have been used: these have proved to be difficult to use or even dangerous in situations where the support has detached itself accidentally.
A still further problem is that of providing for easy and safe maintenance or repair of the lateral conveyors on-site or at a workshop. Head sections often include some parts requiring maintenance, like motor, bearings, belt scraper, safeguarding etc. A safe way of reaching these parts has proved illusive as they are quite high and ground in the worksite is usually soft or uneven, which makes it dangerous to work using ladders. More safe equipment helping the service people to reach high is not often available in the worksites.
It is an object of the present invention to provide a mobile aggregate processing plant which can support lateral conveyors of a greater length than is currently possible with known plant, such as described above in relation to EP 0641607B.
Additionally, it is a further object of the present invention to provide a safe and easy to use support means for a lateral conveyor of an aggregate processing plant which allows the lateral conveyor to be stowed in a transit position within permissible dimensions.
Further, it is an added object of the present invention to provide a support means for a lateral conveyor or an aggregate processing plant which allows the head section of the lateral conveyor to be accessed from the ground for easy maintenance and repair thereof.